This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. In a cell's nucleus, regions of different chromosomes are often in close contact with one another. In some cases, genetic regulatory elements that are encoded on separate chromosomes can communicate with each other, thereby permitting a form of gene regulation that is dependent upon physical proximity between two chromosomes. Recent technological advances have allowed the genetics community to uncover several examples of such interchromosomal interactions, but our understanding of these phenomena remains incomplete. In this proposal, I aim to better understand interchromosomal gene regulation using Drosophila melanogaster as a model system. Specifically, I will assess interchromosomal interactions between various genetic regulatory elements at different locations in the D. melanogaster genome in order to assess the influence of element identity and local genomic context. In addition, I will extend our understanding of the evolutionary history of interchromosomal gene regulation by asking whether this capacity is conserved in other Drosophila species. Through these studies, I aim to understand parameters governing interchromosomal gene regulation, and to better grasp how the spatial organization of the nucleus impacts gene activation.